This invention relates to an elevator control apparatus, and more particularly to an elevator control apparatus in which a stop position command signal required for the floor arrival of an elevator cage can be generated accurately and conveniently.
In a case where, in an elevator which operates among a plurality of floors, a cage is caused to accurately arrive at the respective floors, the start point of a floor arrival sequence and the operating point of a brake are important factors. It is a stop position command signal that determines such floor arrival sequence-start point and brake operation point. The command signals are generated by plates which are disposed in a hoistway in correspondence with the respective floors, and a position detector which is mounted on the cage.
FIG. 7 shows the whole construction of the elevator which is furnished with the stop position command signal-generation means as stated above. Referring to the figure, numeral 11 designates the cage of the elevator, numeral 12 is a counterweight, and numeral 13 a rope which is wound round a sheave 14. The cage 11 and the counterweight 12 are respectively coupled to both the suspending ends of the rope 13. An electric motor 15 drives the sheave 14, a pulse generator 16 generates pulses proportional to the movement distance of the cage 11 on the basis of the revolutions of the motor 15, a counter circuit 17 counts the pulses from the pulse generator 16, and electronic computer 18 receives a movement distance signal 17a from the counter circuit 17 and executes predetermined operations for an elevator running control. Numeral 19 indicates a floor, and numeral 20 a plate, such plates being disposed in a hoistway in correspondence with respective floors. Shown at numeral 21 is a position detector which is mounted on the cage 11, and which transmits an output signal 21a to the electronic computer 18 when the cage 11 has arrived at the level position of each floor.
FIG. 8 is a view showing the operating state of the position detector 21. As seen from this figure, the position detector 21 operates when the cage 11 exists between a short run of 15 mm and an overrun of 175 mm with respect to the floor surface level 19a of each floor 19. In addition, the position detector 21 has operation points for each of UP (ascent) and DOWN (descent) at each floor and delivers the stop position command signal for floor arrival when the cage has come to the corresponding operation point.
In the elevator control apparatus of the above construction, the cage 11 begins to be decelerated when it travels in response to the hall call of a waiting person or a cage call of a passenger and approaches a fixed distance short of a destination floor. Subsequently, the position detector 21 enters the region capable of sensing the plate 20, and output a signal 21a, namely, the stop position command signal is received by the electronic computer 18, whereby this electronic computer decides that the cage 11 has arrived at a point 15 mm short of the destination floor. Then, the electronic computer 18 operates a brake (not shown) assembled in a transmission system for the motor 15 and the sheave 14, and it also starts a floor arrival sequence so as to cause the cage 11 to arrive at the destination floor.
In the prior-art elevator control apparatus as stated above, the generation timing of the stop position command signal when the cage 11 is at a point 15 mm short of the destination floor for determining the start point of the floor arrival sequence as well as the operating point of the brake is determined by the plate 20 which is mounted in the hoistway in correspondence with the pertinent floor. Therefore, the mounting error of the plate 20 directly affects the accuracy of the floor arrival.
Accordingly, at the times of the installation and maintenance of the elevator, the plates 20 of the respective floors must have their positions adjusted exactly in order to enhance the accuracy of the stop position command signals. This has led to the problems that a very long time is expended on the adjustments, and that high degrees of techniques and skill are required therefor.